Coming soon: The Incredible Shrinking Brandon Jacobs

Brandon Jacobs remembers the last time he weighed less than 260 pounds, but the 49ers running back has to travel back a decade to his days at Coffeeville (Kan.) Community College.

As a sophomore, one of Jacobs’ coaches threatened to move him to defensive end if the ever-expanding running back tipped the scales at 260. Of course, that didn’t happen: Jacobs was too good – even at that size – to move him out of the backfield.

And Jacobs, 29, the NFL’s biggest running back, believed bigger was better as he posted back-to-back 1,000-yards seasons and averaged 5.0 yards a carry in 2007-08 with the Giants. In recent years, however, Jacobs, who currently weighs 267, believes his weight has detracted from his game. As a result, he plans to lose about 10 pounds in preparation for the season – getting under 260 for the first time since 2002.

“I think I could move faster,” Jacobs said. “I could hit the hole harder and I could deliver a little bit more of a punch if I’m lighter, versus being heavy and letting the defenders getting up on me.”

In addition to cutting down on carbs, Jacobs is upping his training regimen.

Most notably, he’s doing squats, a lower-body-strengthening exercise he previously avoided, fearing it would tax his knees. The 49ers’ training staff has clearly convinced him a steady diet of squats could tax the defenders trying to tackle him.

Jacobs has developed a reputation for running “soft” during his career, allowing smaller defenders to take him down in one-on-one matchups despite his size.

“I’ve been training here probably 10 times harder than I’ve ever trained,” Jacobs said. “I’m trying to get my body back to how it used to be and strengthen my legs. That was a weak point in me the last couple years, my legs weren’t as strong.”

The good news for the 49ers is that Jacobs only weighs 267 in the aftermath of the Giants’ Super Bowl title last season. After New York won the championship in 2007, Jacobs said he topped out at 285 at the end of his extended celebration: “I just relaxed, ate, took trips,” he said.

He claims to have worn his nearly 300 pounds quite well. Thanks to his 6-foot-4 frame, he can conceal excess weight effectively.

“Which is a good thing for me,” Jacobs said, laughing. “I could be 280 and still look great like this.”